Hall effect elements

Abstract

A Hall effect element is provided with a reduced area while maintaining satisfactory performance. Further, there is provided a Hall effect element with improved long term stability through use of an equipotential plane.

The embodiments of the invention in which an exclusive property or right is claimed are defined as follows: 
     
       1. A Hall effect magnetic sensor, provided as a thin plate having a major surface, with said magnetic sensor sensitive to magnetic fields directed into said major surface, said magnetic sensor comprising: first and second power contacts each in electrical contact with said major surface effectively over first and second areas thereof, respectively, said first and second areas separated by a first separation length in said major surface with said first separation length directed along a first direction; and   first and second signal contacts each in electrical contact with said major surface effectively over third and fourth areas thereof respectively, said third and fourth areas being separated by a second separation length in said major surface with said second separation length directed along a second direction, with each of said first and second areas having a relatively small extent along substantially said second direction as compared with said second separation length.   
     
     
       2. The apparatus of claim 1 wherein said thin plate is a portion of a semiconductor material layer provided in a monolithic integrated circuit, said first direction being such that if electrical current is introduced along said first separation length a substantially minimal electrical response will be obtained between said first and second signal contacts in response to longitudinal stress applied to said monolithic integrated circuit. 
     
     
       3. The apparatus of claim 1 wherein said thin plate has an electrically insulating material layer provided thereover with that portion of said insulating material layer which is over said thin plate having a first metal layer provided at least partially thereover, said first metal layer being electrically connected to permit a selected voltage potential to be provided thereon. 
     
     
       4. The apparatus of claim 2 wherein said semiconductor material layer hae at least one other component device provided in a portion thereof having its major outline in substantially a first quadrilateral figure, said other component device having sides of said first quadrilateral figure lying either substantially parallel or substantially perpendicular to a third direction in said major surface, said third direction being neither parallel nor perpendicular in said major surface to said first direction. 
     
     
       5. The apparatus of claim 2 wherein there is a third direction in said major surface along which said semiconductor material layer can be cleaved relatively easily, said third direction being neither parallel nor perpendicular in said major surface to said first direction. 
     
     
       6. The apparatus of claim 3 wherein said first metal layer covers only a part of said portion of said insulating material layer, and a second metal layer is also provided over another part of said portion of said insulating material layer and is electrically connected so as to permit a selected voltage potential to be provided thereon. 
     
     
       7. The apparatus of claim 4 wherein said third direction is substantially parallel to a direction in said monolithic integrated circuit along which said semiconductor material can be cleaved relatively easily. 
     
     
       8. The apparatus of claim 5 wherein said thin plate has its major outline in substantially a first quadrilateral figure and two sides of said first quadrilateral figure are substantially parallel to each other and to said third direction and two other sides of said first quadrilateral figure are substantially parallel to each other but substantially perpendicular to said third direction. 
     
     
       9. The apparatus of claim 6 wherein said first metal layer is electrically connected to said first signal contact and said second metal layer is electrically connected to said second signal contact. 
     
     
       10. The apparatus of claim 7 wherein said thin plate has its major outline in substantially a second quadrilateral figure and two sides of said second quadrilateral figure are substantially parallel to each other and to said third direction and two other sides of said second quadrilateral figure are substantially parallel to each other but substantially perpendicular to said third direction. 
     
     
       11. The apparatus of claim 10 wherein said semiconductor material layer is an epitaxial layer of a first conductivity type provided on a semiconductor material substrate of an opposite conductivity type and said thin plate is provided by junction isolation in said semiconductor material layer, as is said other component device, such that said thin plate has characteristics of a two terminal monolithic integrated circuit resistor between said first and second power contacts, said first and second power contacts and said first and second signal contacts being parts of a metallization interconnection network with said first and second areas capable of being contained in a circular figure of a selected diameter which is relatively small as compared with said second separation length. 
     
     
       12. A Hall effect magnetic sensor, provided in a monolithic integrated circuit in a first semiconductor material layer, with said magnetic sensor having its major outline in substantially a first quadrilateral figure in a first major surface of said first semiconductor material layer and with said magnetic sensor sensitive to magnetic fields directed into said first major surface, there being also at least one other component device provided in a second semiconductor material layer having its major outline in substantially a second quadrilateral figure in a second major surface of said second semiconductor material layer of semiconductor material, said magnetic sensor comprising: first and second power contacts each in electrical contact with said first major surface effectively over first and second contact areas thereof, respectively, said first and second areas separated by a first separation length in said first major surface with said first separation length directed along a first direction;   first and second signal contacts each in electrical contact with said first major surface effectively over third and fourth areas thereof, respectively, said third and forth areas being separated by a second separation length in said first major surface with said second separation length directed along a second direction, with each of said first and second areas having a relatively small extent along substantially said second direction compared with said second separation length; and   said first direction being such that, if electrical current is introduced along said first separation length, substantially minimal electrical response will be obtained between said first and second signal contacts in response to longitudinal stress applied to said monolithic integrated circuit, there being two sides of each of said first and second quadrilateral figures substantially parallel to a third direction in said integrated monolithic circuit along which semiconductor material in said second semiconductor material layer can be cleaved relatively easily and two other sides each of said first and second quadrilateral figures being substantially perpendicular to said third direction.   
     
     
       13. The apparatus of claim 12 wherein said first and second semiconductor material layers are first and second portions respectively of an epitaxial layer of a first conductivity type provided on a semiconductor material substrate of an opposite conductivity type and said magnetic sensor is provided by junction isolation in said epitaxial layer, as is said other component device, such that said first portion of said epitaxial layer has characteristics of a two terminal monolithic integrated circuit resistor between said first and second power contacts, said first and second power contacts and said first and second signal contacts being parts of a metallization interconnection network and each of these said contacts being relatively close to a different vertex of said first quadrilateral figure when compared with said first and second separation lengths, said first and second areas being capable of being contained in a circular figure of a selected diameter which is relatively small compared with said second separation length. 
     
     
       14. The apparatus of claim 13 wherein said first portion of said epitaxial layer has an electrically insulating material layer provided thereover with that portion of said insulating material layer which is over said first portion of said epitaxial layer having a first metal layer provided at least partially thereover, said first metal layer being electrically connected to permit a selected voltage potential to be provided thereon. 
     
     
       15. The apparatus of claim 14 wherein said first metal layer covers only a part of said portion of said insulating material layer, and a second metal layer is also provided over another part of said portion of said insulating material layer and is electrically connected so as to permit a selected voltage potential to be provided thereon. 
     
     
       16. The apparatus of claim 15 wherein said first metal layer is electrically connected to said first signal contact and said second metal layer is electrically connected to said second signal contact. 
     
     
       17. A Hall effect magnetic sensor provided as a thin plate having a first major surface, said thin plate, absent external influences, having its conductivity determined throughout primarily by a single kind of effective charge carrier, with said magnetic sensor sensitive to magnetic fields directed through said first major surface, said sensor comprising: first and second power contacts each in electrical contact with said first major surface effectively over first and second areas thereof, respectively;   first and second signal contacts each in electrical contact with said first major surface effectively over third and fourth areas thereof, respectively;   an electrically insulating material layer having a second major surface, said insulating material layer provided over said thin plate on said first major surface; and   a first metal layer provided on a protected area in said second major surface which is over at least a part of that portion of said insulating material layer on said thin plate which is between said first and second power contacts and between said first and second signal contacts, said protected area being substantially larger than any of said first, second, third or fourth areas, said first metal layer being electrically connected so as to permit a selected voltage potential to be provided thereon.   
     
     
       18. The apparatus of claim 17 wherein said first metal layer covers only a part of said portion of said insulative layer which covers said thin plate and a second metal layer is also provided over another part of said portion of said insulative layer, said second metal layer being electrically connected so as to permit a selected voltage potential to be provided thereon upon energization of said magnetic sensor. 
     
     
       19. The apparatus of claim 17 wherein said thin plate is a portion of an epitaxial semiconductor material layer of a first conductivity type formed on a semiconductor material substrate of an opposite conductivity type and said thin plate is formed by junction isolation in said epitaxial semiconductor material layer. 
     
     
       20. The apparatus of claim 18 wherein said first metal layer is connected to said first signal contact and said second metal layer is connected to said second signal contact.